#169 Admin on teams

* adds admin column on team index view
* refactors Team model, so multiple members can become admins
* adds team migration for switch from fkey->m2m structure
* renames 'Group' to 'Permission' on user index view to avoid confusion between 'Groups' and Teams
* adds new autocomplete route for team-admin selection based on already selected members of the TeamForm

user/templates/user/index.html

@@ -18,7 +18,7 @@
                     <td>{{user.email}}</td>
                 </tr>
                 <tr>
-                    <th scope="row">{% trans 'Groups' %}</th>
+                    <th scope="row">{% trans 'Permissions' %}</th>
                     <td>
                         {% for group in user.groups.all %}
                             <span class="badge badge-pill rlp-r">{% trans group.name %}</span>